Not Right
They assumed that the tree was hollow, and this was not entirely wrong. However, it meant that there should have been light going through the trunk. This was not the case for some reason. It meant that the tree was not actually hollow or that there was something down there. Which one was it?

Not Right
Black Hole
People who saw the tree trunk from afar claimed that there seemed to be a black hole of sorts inside it. Regardless of how they looked at it, the tree was definitely intriguing. The most rational explanation was that there was a stem growing inside of it. However, the reality was far stranger than that!

Black Hole